Thanks to the more than 100-hour integration with MUSE AO in the MXDF [1]}, we were able to examine the existence of \(\mbox{Ly$\alpha $}\)  haloes around UV-selected star-forming galaxies at \(z\simeq 2.9\) –\(4.4\) . With the MXDF data, we constructed a sample with a \(F775W\le 27.5\)  mag cut, with spectroscopic redshift constraints. We confirmed that all of 26 sources with \(z_{\rm p}\simeq 2.9\) –\(4.40\)  have a close spec-\(z\)  estimation to their photo-\(z\) , which implies high completeness values of our spec-\(z\)  assignments. We used 21 galaxies at \(z_{\rm s}=2.9\) –\(4.4\) , which include 17 isolated sources in HST images. The \(M_{1500}\)  range of our sample is -20 to -18 mag, enabling us to construct a UV-bright sample over the redshift range (11 sources, \(-20.0\le M_{1500}\le -18.7\) ). Our major results are summarized as follows.
